Control of petrol carburetors for aeroplane and airship engines



Ahg. 12 1924. 1,504,524

- F. SMAL ET AL.

CONTROL OF PETROL QARBLJRETORQEOR AEROPLANE AND AIRSHIP ENGINES FiledNew. 1'7. 1920 WM N1]? SmaL a/zd/ Patented Aug. 12, 1924.

FFIRMIN'SMAL, or ooU'rHuINmEneIUi/i, Ann-'oAMInnn'rURo'uoIs, or rams,FRANCE.

' CONTROL OF PETROL C ARBURET O RS AND AIRSHIZP E-NGINES.

Application filed November i7, 1-920. serial No. 424;688.

(GRANTED 'UNDER TI-IEPROVISIONS OF THEACT- OF MARCH 3,'1921,-41 STAT. L,1313.)

T 0 all whom it may concern:

Be it known that we, FIRMINSMAL and CAMILLE TURQUOIS,Sl1bj8CtS of theKing of Belgium and of France, respectively, residing at Couthuin,Belgium, and Paris, France, respectively, have invented anew and usefulImprovement in the Control of Petrol Carburetors for Aeroplane andAirship Engines .(for which we have filed application inllrance Nov-15,1919,Patent No. 516,826, and-in Belgium, Sept, 28, 1920),of which thefollowing is a specification.

This :invention "relates to petrol carburetorsfora eroplane engines, andgreatly improves their working. I

It is known, that such carburetors are pro vided with a suitableapparatus "forxcorrecting or regulating the carburetor, according to thedifferent altitudes of the aeroplane.

Actually most of these apparatus are hand controlled.

The improvement, according to the present application, consists in anarrangement assuring the automatic working of such apparatus forregulating the carburetor by means of the varying pressure and temperature at the different heights.

As shown by the diagrammatic drawing, annexed as an illustration of thepresent invention, the arrangement comprises 1.Two pistons 1 and 2,withoutpistonrings and moving respectively in two single actingcylinders 3 and 4 in such a way that one side of each piston is incommunication with the outside air.

2. A reservoir 5, said reservoir being of metal, air-tight,indifiormable and of good heat conductibility.

3.An airtight reservoir 6 of metal, placed between the two cylinders 3and 4 and the reservoir 5, and filled with lubricating oil by the tube7, the level of the oil in the reservoir 6 being kept constant by meansof known regulating apparatus such as shown in the sketch, andcomprising the float 9 and the needle-valve 8.

4.A tube 10 connecting the reservoir 5 to the reservoir 6 at a pointabove the constant oil level.

5.Two tubes 11 and 12 connecting respectively the two cylinders 3 and 4to the reservoir 6 at a point below the constant oillevel.

6P.A system comprising a lever 13 and "pressure as the outside air.

connecting rods 14 and 15 interconnecting the two pistons land 2 in sucha manner, that the whole Wlll be equilibrated as far as gravity isconcerned.

7.A rod 16 connected to the lever 13 and transmitting the motion of thetwo pistons 1 and2 to the 'altimetric regulating apparatus of thecarburetor.

8f.-A spring 17 regulating the movement of the pistons 1 and 2 whateverbe their positions. The plan of the drawings is that of'the ground. Thereservoir is here filled with atmospheric air at the same temperatureand As the dying machine rises, the -atmosphericQpressure on the pistons1 and 2 andthe temperature change, the temperature o'fthe outside airbeing communicated by conductibility to the air contained in thereservoir 5, the volume of this reservoir remaining constant the insideair pressure must necessarily vary.

These variations in pressure and temperature of the exterior air causeconsequently a to and fro motion of the pistons 1 and 2, said movementcorresponding to the difference in pressure of the outside and theinside air of the reservoir 5, this latter pressure being communicatedto the oil of the reservoir 6 which transmits said pressure to thepistons. The motion of the pistons 1 and 2 is suitably transmitted bythe connecting rod 16 to the regulator of the carburetor.

It is shown above that the pressure of the air inside the reservoir 5 istransmitted to the pistons 1 and 2 by means of the oil of the reservoir6. The particular working of this reservoir 6 constitutes one of thecharacteristics of this invention. Not only does the oil of thereservoir 6 transmit the pressure of the air contained in 5 to thepistons 1 and 2 but it serves also to lubricate said pistons andprevents the escape of air between the reservoir 5 and the atmospherealthough the pistons have no rings the oil escaping between the pistonsand the cylinders 3 and 4 being continuously replaced by the feedingpipe 7.

Further, the level of the oil remaining constant, the volume of the aircontained in 5, 10 and that above the oil in 6 remains also constant,which is an essential and necessary condition for the good technicalworking of the whole system.

Cir

It should be noted that the diameter of the cylinders 3 and 4 is madesufficiently large in relation to that of the respective pistons 1 and 2to allow the escape round said pistons of any excess of oil in thesystem in order to avoid the oil-level rising when the atmosphericpressure increases; this escape of oil in'excess does not offer anydisadvantage provided the needle-valve 8 and the supply-pipe 7 are ofsufficient size to allowthe admission of oil at a rate sufficient tomaintain the constant level in the tank 6 in any case and at any time.

On the contrary, it has been found in practice that the more oil inexcess escapes round the'pistons, the better the apparatus works, thelubrication being thereby improved. It may be observed that thequantity' of oil admitted by the needle valve is immaterial as far asthe operation of the apparatus is concerned, provided a rate ofadmission of oil exceeding the maximum amount which could escape ispossible.

We'claim: i 1 An apparatus for automatically controlling a carburetorfor aeroplanes, according to the changes in atmospheric pressure andtemperature, dueto diflterent altitudes, said apparatus comprising anairtight reservoir,

filled with air, and communicating with another airtight reservoir,partially filled with air and partially with oil, the oil level beingkeptat a constant height by means of an oil feeding pipe and a suitablecontrolling device, such as a float combined with a needle valve, theoil of the reservoir communicating by means of two tubes with a pair ofcylinders in each of which moves a single acting piston, not providedwith rings, and the free side of which is open to the pressure of theoutside air, the connecting rods of the pistons being attachedrespectively to the two arms of a lever pivoted at a point between itsends in such a way that the combination of pistons, levers andconnecting rods is balanced, the two extremities of the lever beingrespectively attached, one to a reaction spring and the other to asuitable cable or rod connected with the altimetric correcting device ofthe carburetor.

In testimony thereof We signed hereunto our names in the presence of twosubscrib- 'ing witnesses.

FIRMIN SMAL. TURQUOIS. Vitnesses J. GRAN,

CURTIs T. EVERETT.

